Ethynylaryl amines and processes for their preparation

ABSTRACT

This application discloses arylethynylphenylcyclopropylamines and processes for their preparation. These amines exhibit monoamine oxidase (MAO) inhibiting activity.

United States Patent [191 Remy [451 Sept. 2, 1975 ETI-IYNYLARYL AMINES AND PROCESSES FOR THEIR PREPARATION [75] Inventor: David C. Remy, North Wales, Pa.

[73] Assignee: Merck & Co., Inc., Rahway, NJ.

[22] Filed: Aug. 19, 1974 [21] Appl. No.: 498,829

[52] U.S. Cl.... 260/5705 CA; 260/668 R; 260/247; 260/326.87; 260/243 R; 260/25] R [51] Int. Cl. ..C07C 91/16; C07D 295/02;

[58] Field of Search 260/5705 CA, 668 R [56] References Cited I UNITED STATES PATENTS 3,050,559 8/1962 Burger 260/5705 CA 3,207,785 9/1965 Kaiser et a1. 260/5705 CA X 3,532,749 10/1970 Biel et al. 260/5705 CA X 3,646,146 2/1972 Tcotino et al. 260/5705 CA X 3,719,712 3/1973 Remy 260/5709 FOREIGN PATENTS OR APPLICATIONS 973,887 10/1964 United Kingdom 260/5705 CA Primary ExaminerAllen B. Curtis Attorney, Agent, or FirmDaniel T. Szura; .1. Jerome Behan ETI-IYNYLARYL AMINES AND PROCESSES FOR THEIR PREPARATION BACKGROUND OF THE INVENTION:

This invention relates to arylethynylarylcyclopropylamines, their method of preparation and pharmaceutical use.

Arylethynylaralkylamines of the general formula where R and R are hydrogen or other substituents. These novel compounds have activity as monoamine oxidase inhibitors. Inhibition of monoamine oxidase is an activity useful in the treatment of mental depression.

SUMMARY OF THE INVENTION Compounds having the formula:

wherein L is aryl, preferably phenyl and R and R are various substituents, preferably hydrogen; and nontoxic pharmaceutically acceptable salts thereof; methods for preparing these compounds, and use as monoamine oxidase inhibitors.

DESCRIPTION OF THE PREFERRED EMBODIMENTS:

The present invention is embodied broadly in compounds which are 1,2-diaryl derivatives of acetylene wherein one of the aryl substituents is an aromatic ring having at least one of its hydrogens replaced by an aminocyclopropyl radical, and in which the other aryl substituent includes unsbustituted homocyclic or heterocyclic aryl groups and substituted homocyclic and heterocyclic aryl groups.

A preferred class of compounds of the present invention are susbstituted cyclopropylamines having the formula:

wherein L is aryl, and R and R l when separate, are independently selected from hydrogen, alkyl and alkenyl, cycloalkyl, perfluoroalkyl, aryl, acyl, and formyl, and (2) when joined are a 5-6 membered heterocyclic group.

Formula 1 compounds includes those in which L is biphenylyl, napthyl, indanyl, indenyl, phenyl or substituted phenyl having one or more, preferably one to three substituents selected from the group consisting of an alkyl having up to 6 carbon atoms, an alkenyl group having up to 6 carbon atoms, a perfluoroalkyl group having up to 4 carbon atoms, a phenyl or a substituted phenyl radical, a dialkylamino group having up to 8 carbon atoms, an alkylsulfonylamino group having up to 4 carbon atoms, hydroxyl, an alkoxy group having up to 4 carbon atoms, mereapto, an alkylmercapto group having up to 4 carbon atoms or a halogen such as fluoro, ehloro, bromo or iodo and R and R are separate.

An especially preferred group of compounds of the invention are those having the formula:

wherein X is selected from halogen, including C], 1 Br and F. hydrogen, lower alkoxy of l4 carbons, preferably methoxy, lower alkyl of from l4 carbons, preferably methyl, hydroxy, phenyl, alkyl, mereapto, alkyl sulfonyl, sulfamoyl, and trifluoromethyl; n is l or 2 and R and R are independently selected from hydrogen and lower alkyl substituents having from 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms, and methyl most preferably; and pharmaceutically acceptable salts thereof.

Still more preferred compounds of the present invention are those having the formula:

wherein X is selected from halogen including Cl, F l

and Br, -CF;,, C -C alkyl, C -C alkoxy, and phenyl and R and R are independently selected from hydrogen and C,C;, alkyl; and pharmaceutically acceptable salts thereof. Most preferred compounds are l-[4- (phenylethynyl)phcnyl]cyclopropylamine having the formula:

Quin Q C s C Ll c EC CH.,CH2

l-[4-(phenylethynyl )phenyl]cyclopropyl-N,N-di-tbutylamine;

l-[4( 3-iodophenylcthynyl )phenyl]- cyclopropylamine;

l-[ 4 3 ,S-dibromophenylethynyl )phenyl ]cyclopropyl-N-propylamine;

cyclohexylphenylethynyl )phenyl cyclopropyl-N- cyclopropylamine;

1- 4-( phenylethynyl )phenyl ]cyclopropylN- hexylamine and the like; and their non-toxic pharmaceutically acceptable salts.

The non-toxic pharmaceutically acceptable salts of the present amines are generally the acid addition salts. They are prepared by reacting the amine compound with sufficient acid to neutralize at least one, and preferably all the basic nitrogens in said amine. Useful salts are those of the present cyclopropyl amine and an inorganic acid or an organic acid. Useful inorganic acids are the hydrohalo acids such as HCl and HBr, sulfuric acid, phosphoric acid, and the like. Useful organic acids are those such as sorbic acid, citric acid, 1 malic acid, maleic acid, tartaric acid, lactic acid, propionic acid, succinic acid, adipic acid and the like Examples of useful salts are l-[4-( phenylethynyl )phenyl cyclopropylamine hydrochloride l-[4-( p-tolylethynyl )phenyl cyclopropyl-N- methylamine hydrogen maleate l-[4-( o-bromophenylethynyl )phenyl cyclopropylamine succinate l-[4-(B-naphthylethynyl)phenyl]cyclopropyl-N- amyl dihydrogenphosphate and the like.

REACTION SEQUENCE A Chlorinating Agent cyanide reagent Hydrolysis l.-C E c c c i (l) Azidc Formation (2) Curtius Rearrangement (3) Hydrolysis The final product (6) can be converted to corresponding N-substituted or N,N-disubstituted compounds by any applicable reaction.

The following example illustrates, but does not limit, the process of Sequence A.

EXAMPLE 1 A. 4-( Phenylethynyl )phenylacetonitrile Anal. Calcd. for C H Cl: C, 79.47; H, 4.89. Found: C, 79.60; H 4.98.

A mixture of 3.72 g. (0.076 mole) of sodium cyanide in 30 ml. of dry dimethylsulfoxide is heated to 9095. On cooling to 35, the mixturee forms a gelatinous mass that is stirred manually while 8.0 g. (0.0354 mole) of the above chloride is added. The mixture is stirred overnight and is poured into 400 ml. of water. The pre cipitate is collected, dissolved in benzene, washed with water, dried over magnesium sulfate, and the solvent removed. The residue is recrystallized from cyclohexane to yield 13.25 g. (88%) of 4-(phenylethynyl) phcnylacetonitrile, m.p. 7670. An analytical sample is prepared by sublimation at 80 (0.05 mm), m.p. 7880.

Anal. Calcd. for C H NC, 88.45; H,5.l; N,6.45.

Found: C, 88.76; H, 5.10; N, 6.31.

B. l-[4-( Phenylethynyl )phenyl cyclopropane carbonitrile Sodamide, prepared from 0.46 g. (0.02 g. atom) of sodium and suspensed in ml. of ether, is stirred at room temperature while a solution of 2.17 g. (0.01 mole) of 4-(phenylethynyl)phenylacetonitrilc in ml. of ether is added dropwise. The mixture is refluxed for 4 hours, and then is cooled in an ice-salt bath while a solution of 1.43 g. (0.01 mole) of 1-brom0-2- chloroethanc in 2 ml. of ether is added dropwise. The mixture is stirred overnight at room temperature, refluxed for 4 hours, cooled, and diluted with ml. of water. The aqueous phase is separated, re-extracted with ether, and the combined organic phases are washed with water and dried over magnesium sulfate. The oily solid residue obtained by evaporation of the ether is freed from oil by trituration with ether and sub limed at 80 (0.5 mm) to yield 1.28 g. (53%) of 1-[4- (phenylethyny1)phenyl ]cyclopropane carbonitrile, m.p. 9395C.

Anal. Calcd for C H NzCm 88.86; H, 5.39; N.576.

Found: C, 88.99; H, 5.55; N, 5.52.

C. l'[4-( Phenylethynyl )phenyl]cyclopropane carboxamide A mixture of 3.49 g (0.014 mole) of l[4- phenylethynyl)phenyl]cyclopropane carbonitile, 20 drops of potassium hydroxide, 18 ml. of hydrogen peroxide, and 140 ml. of methanol is heated at 5560 for 8 hours, with additions of 10 ml. of 30% hydrogen peroxide and 10 drops of 25% potassium hydroxide after 4.5 hours and 5 ml. of 30% hydrogen peroxide after 6 hours. The product crystallization from benzenc-cyclohexane gives pure l[4- (phenylethynyl )phenyl ]cyclopropane carboxamide, m.p. l74175.5.

Anal. Caled for C H NO:C, 82.73; H, 5.78; N, 5.36.

Found: C, 83.07; H, 5.91; N, 5.32.

D. l-[4-(Phenylethynyl)phenyljcyclopropane carboxylic acid A mixture of 2.92 g. (0.0112 mole) of l-[4- (phenylethynyhphenyllcyclopropane carboxamide, 90 ml. of methanol, 90 ml. of tetrahydrofuran, and 60 ml. of 10% sodium hydroxide is refluxed for 66 hours. After removing solvents, the sodium salt is collected and washed with water and methylene chloride. The precipitate is stirred in a mixture of 6N hydrochloric acid and 'methylene chloride untill all the solid is dissolved. The organic phase is removed, washed with water, dried (MgSO filtered, and the solvent removed to give 1.95 g..(66%) of l-[4-(phenylethynyl)phenyl]- cyclopropane carboxylic acid, m.p. 214218. The product is recrystallized from benzene-cyclohexane, m.p. 2l5-2l8.

Anal. Calcd for c H O zc, 82.42; H, 5.38. Found: c, 82.36; H, 5.37.

E. l-[4-(Phenylethynyl)phenyljcyclopropylamine.

To a stirred suspension of 2.52 g. (0.0096 mole) of 1-[4-(phenylethynyl)phenyl]cyclopropane carboxylic acid in 12 ml. of acetone 2 ml. of water, cooled in an ice-salt bath, is added dropwise a solution of 1.13 g. (0.0112 mole) of triethylamine in 9.5 ml. of acetone followed by a solution of 1.31 g. (0.012 mole) of ethyl chloroformate in 5.5 ml. of acetone. After stirring for 0.5 hours, a solution of 0.94 g (0.0145 mole) of sodium azide in 3 ml. of water is added. After stirring for one hour, the mixture is poured into ml. of water and the azide is extracted into toluene. The water washed and magnesium sulfate dried toluene extract is heated for 0.5 hour on a steam bath, evaporated to about 15 ml. and benzyl alcohol (2 ml.) is added. The mixture is heated for 6 hours on the steam bath and if filtered hot. N-Benzyloxycarbonyl-1-[4 -(phenylethynyl )phenyl]cyclopropylamine, 2.9 g. (82%) precipitated from the cooled filtrate. The material is recrystallized from ben zene-hexane and from isopropyl alcohol, m.-.

Anal. Calcd for C ,,H NO C, 81.72; H, 5.76; H, 3.81.

Found: C, 81.72; H, 5.81; N, 3.76'.

A solution of the above benzylurethane 1.0 g., 0.0027 mole) and 8 g. of potassium hydroxide in 40 ml. of n-butanol is heated at l l5l20 for 7 hours, cooled, and poured into 250 ml. of water. The aqueous layer is separated and extracted with benzene. The combined organic phases are washed with water and extracted with 0.5 M citric acid. Neutralization of the acid extract with 40% sodium hydroxide precipitated 0.51 g. (80%) of 1-[4-( henylethynyl )pheny1]- cyclopropylamine as white crystals, m.p. l12116. The product is recrystallized from hexane, m.p.

Anal. Calcd. for C H N:C, 87.51; H, 6.48; N, 6.00.

Found: C, 87.27; H, 6.44; N, 6.12.

Corresponding cyclopropylamines are prepared when the following benzyl alcohols are substituted for the 4-(phenylethynyl)benzyl alcohol in the Example 1 procedure:

4( 3-cyclohexylphenylethynyl)benzylalcohol,

4-( 2,4-xylylethynyl )benzyl alcohol, 4-(4-t-butylphenylethynyl)benzyl alcohol,

4-( 3-ethoxyphenylethynyl)benzyl alcohol,

4-( 3,5-dibromophenylethynyl)benzyl alcohol 4-( diphenylylcthynyl)benzyl alcohol and the like.

The Nmonoand N,N-dialkyl substituted derivatives of these cyclopropylamines are prepared by available alkylation methods, e.g. treatment with formaldehyde and HCOOH or acylation of the amine followed by reduction. I 7

Another method for preparing. the present cycloalkylamines is illustrated by the following reaction sequence:

REACTION SEQUENCE B The reaction sequence utilizes an aryl metal acetylide and a suitable aryl iodide to prepare the amine compounds directly. M in the above equation may be Ag or Cu while L, R and R are as defined above. A most suitable acetylide is the cuprous acetylide C E C-Cu.

The compounds of the present invention, both the free amines and their pharmaceutically acceptable salts, are pharmacologically active in inhibiting monomaine oxidase. This activity was demonstrated by de termining the effect of an amine of the present invention on brain serotonin. The following test procedure TABLE 1 Determination of MAO Inhibition by Serotonin Level Test Animal Treatment Serotonin Level (,u/g.)

1 none 0.75 2 150 mg/kg. of [.41

Example 1 compound The data shows that the serotonin level of the mice treated with an amine of the present invention was substantially increased. Since inhibition of monoamine oxidase is known to effect an increase in serotonin level, the data in Table 1 clearly indicates that the Example 1 compound is a monoamine oxidase inhibitor.

In addition to the in vivo MAO inhibition demonstrated by the Example 1 compound, comparable in vitro MAO inhibition by the Example 1 compound was also observed.

Analogous MAO inhibition is effected by any of the cyclopropylamines (and/or salts thereof) disclosed herein.

Since it is recognized that an increase in serotonin level by MAO inhibition stimulates the central nervous system, MAO inhibitors have found use in treatment of patients suffering from mental depression. The amount of MAO inhibitor compounds to be used in treating mental depression will vary, depending on the severity of the depression, the physical condition of the patient, the relative activity of the compound used, the mode of administration and other factors. Generally, daily doses ranging from 0.01 to 15 mg. per kilograms can be used. The compounds of the present invention can be administered by any suitable mode such as orally, intravenously, intraperitoneally etc. Suitable dosage forms are used depending on the mode of administration. The compounds of the present invention can be administered as the free amines or preferably as pharmaceuti' cally acceptable salts. For oral administration, the compounds can be used in tablets, capsules, microcapsules, in palatable liquid carriers and the like. For administration by injection, the compounds can be conveniently dissolved or dispersed in a pharmaceutically acceptable carrier.

Claims to the invention follow:

What is claimed is:

1. Compounds selected from a. substituted cyclopropylamincs having the formula:

LC E C wherein L is aryl, and R and R are or each hydrogen, alkyl alkenyl, and

b. non-toxic, pharmaccutically acceptable salts of 2. Compounds of claim 1 wherein L is phenyl or substituted phenyl.

3. Compounds of claim 1 wherein L is phcnyl.

4. Compounds of claim 3 wherein R and R are each I hydrogen or C C alkyl.

5. Compounds of claim 4 wherein R and R are each hydrogen.

6. A process for preparing compounds having the formula:

wherein L is aryl, and R and R are each hydrogen, alkyl, or alkenyl, which comprises reacting an iodo compound having the formula:

with an acetylide having the formula:

wherein M is Ag or Cu.

7. The process of claim 6 wherein L is phenyl or substituted phenyl and M is Cu.

8. The process of claim 7 wherein L is phenyl. 9. The process of claim 8 wherein R and R are each 10 hydrogen or C, C alkyl.

10. The process of claim 9 wherein R and R are each hydrogen.

11. A process for preparing compounds having the formula C --CH- H C a C Z wherein X in independently selected from halogen, alkyl, phenyl, hydroxy, alkoxy, cycloalkyl, and CF,,, n is selected from 0, l and 2 which comprises:

(l) treating a compound having the formula:

w c c-- -CH. ,OH

with a chlorinating agent to produce the chloro compound c a c Q CHr ,Cl

(2) treating sa1d chloro compound with a sultable cyanide reagent to prepare the corresponding cyano compound having the formula C i C G CH2 CN (3) treating said cyano compound with sodamide and l-bromo-2-chloroethane to produce a cyclopropyl cyano compound having the formula:

(4) hydrolyzing said cyclopropylcyano compound to produce the corresponding carboxylic acid having the formula:

(5) converting said carboxylic acid to the corresponding azide,

(6) rearranging said azide by heating in a suitable solvent, and

(7) hydrolyzing the product from (6) to produce said formula( I )amine.

12. The method of claim 11 wherein n is O, and R and R are each hydrogen and in step (1) said chlorinating agent is SOCl in step (2) said cyanide reagent is NaCN, and in step (6) said solvent is benzyl alcohol, the product obtained having the formula:

13. A process for preparing salts of compound having the formula wherein L, R and R are as defined in claim 1, and said compound has one or more basic amine nitrogens, which comprises treating said compound with sufficient inorganic or organic acid to neutralize at least one of said basic amine nitrogens.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3 903 DATED September 2, 1975 INVENTOR(S) David C. Remy It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In Column 10, Claim 1, line 40 should read:

wherein L is aryl, and R and R are each hydrogen,

In Column 10, Claim 1, line 41 should read:

alkyl or alkenyl, and

- Sign! and Scalcd this second Day of December1975 [SEAL] RUTH C. MASON C. MARSHALL DAMN Arresting Of ficer Commissioner nfPatenls and Trademark! 

1. COMPOUNDS SELECTED FROM A. SUBSTITUTED CYCLOPROPYLAMINES HAVING THE FORMULA:
 2. Compounds of claim 1 wherein L is phenyl or substituted phenyl.
 2. treating said chloro compound with a suitable cyanide reagent to prepare the corresponding cyano compound having the formula
 3. treating said cyano compound with sodamide and 1-bromo-2-chloroethane to produce a cyclopropyl cyano compound having the formula:
 3. Compounds of claim 1 wherein L is phenyl.
 4. Compounds of claim 3 wherein R1 and R2 are each hydrogen or C1 - C6 alkyl.
 4. hydrolyzing said cyclopropylcyano compound to produce the corresponding carboxylic acid having the formula:
 5. converting said carboxylic acid to the corresponding azide,
 5. Compounds of claim 4 wherein R1 and R2 are each hydrogen.
 6. A process for preparing compounds having the formula:
 6. rearranging said azide by heating in a suitable solvent, and
 7. hydrolyzing the product from (6) to produce said formula(I)amine.
 7. The process of claim 6 wherein L is phenyl or substituted phenyl and M is Cu.
 8. The process of claim 7 wherein L is phenyl.
 9. The process of claim 8 wherein R1 and R2 are each hydrogen or C1 - C6 alkyl.
 10. The process of claim 9 wherein R1 and R2 are each hydrogen.
 11. A process for preparing compounds having the formula
 12. The method of claim 11 wherein n is 0, and R1 and R2 are each hydrogen and in step (1) said chlorinating agent is SOCl2, in step (2) said cyanide reagent is NaCN, and in step (6) said solvent is benzyl alcohol, the product obtained having the formula:
 13. A process for preparing salts of compound having the formula 